<h2>First Component</h2>
<!--准备构建子路由-->
<nav>
  <ul>
    <li><a routerLink="child-a">Child A</a></li>
    <li><a routerLink="child-b">Child B</a></li>
    <li><a routerLink="../second">second-page(1)</a></li>
    <li><button (click)="toSecondPage()">second-page(2)</button></li>
  </ul>
</nav>
<div class="router-box">
  <router-outlet></router-outlet>
</div>




